Alarm clock



p i 1949- G. s. ANDREWS 2,467,925

ALARM CLOCK Filed Nov. 4, 1946 INVENTOR.

GEORGE E. ANDREWS BY I x Patented Apr. 19, 1949 ALARM CLOCK George S. Andrews, Greenwich, Conn., assignor to The United States Time Corporation, Waterbury, Conn., a corporation of Connecticut Application November 4, 1946, Serial No. 707,662

4 Claims. 1

This invention relates in general to alarm clocks of the type wherein the time train and the alarm train are driven by a single main spring. In clocks of this type, it is desirable that some means be provided to limit the operation of the alarm train so that the alarm will not run continuously until the spring is completely unwound. If some means were not provided to limit the operation of the alarm to a definite length of time, the alarm would continue to be sounded until the main spring was completely unwound and the time train would, of course, also stop and that would obviously be undesirable.

Also, in an alarm clock, it is desirable to have the frame plates as close together as possible, within reasonable limits, so that the clock case will not have to be made unduly deep to take care of housing the movement.

It is an object of this invention to provide an alarm clock wherein the time train and the alarm train are driven by a single spring and to provide a means for limiting the operation of the alarm train to a definite length of time.

It is specifically an object of this invention to provide an inexpensive though efiicient means for limiting the movement of the alarm train main wheel to one revolution or less than one revolution during the operation of the alarm.

It is also a specific object of this invention to provide a means for stopping the alarm train main wheel after one revolution during the sounding of the alarm which will be compact and will not make it necessary to position the frame plates an undue distance apart to accommodate said stopping means.

Referring now to the drawing for a specific embodiment of the invention:

Fig. 1 is an exploded view of the motor of the clock showing parts of the time train and the alarm train.

Fig. 2 is an enlarged view of the alarm train main wheel and its hub.

Fig. 3 is a side elevational View of the coiled main spring.

Fig. 4 is a side elevational view of the hub per se of the alarm train main wheel.

Fig. 5 is a view showing a cross section of several different embodiments of a member used as part of the stop mechanism.

In Fig. 1, the frame plates of a clock movement are shown at H) and HE. A winding arbor I4 provided with a suitable key, not shown, is rotatably mounted in bearing openings i6 and I8 provided in the plates ID and I 2 respectively. A hub 20 of the alarm train main wheel 22 is force-fitted,

upon the winding arbor I4. The hub 20 and alarm train main wheel 22 are secured together in any suitable manner, and the hub 20 is provided with a flange 24. As shown in Fig. 1, the alarm train main wheel 22 meshes with a pinion 26 which is drivingly connected with the second wheel (not shown) of the alarm train in the usual manner. A one-way drive connection (not shown) is incorporated at a suitable location in the time train to permit winding. Rotatably mounted upon the winding arbor I4 is a hub 28 of the time train main wheel 30. At 32 is shown a barrel, and the barrel 32, time train main wheel 30, and hub 28 are secured together in any suitable manner to form a unitary assembly. Hub 28 is coaxial and registers with an axial opening (not shown) in the lower portion of hub 20 when the parts are assembled. The time train main wheel 30 meshes with a pinion 34 formed integrally with, or suit-r ably connected to, a wheel 36 which is the second wheel of the time train. The main spring of the clock which drives both the time train and the alarm train is shown at 3B, and this spring fits within the barrel 32 and is drivingly connected to the barrel by means of a tail 4%] shown in Fig. 3. The inner end of the main spring is provided with a hook 42 which fits within a notch provided in hub 20.

The mechanism thus far described operates in the following manner. When the winding arbor I4 is turned in a clockwise direction, the main spring 38 will be wound and will then drive the time train main wheel 35. Any suitable and conventional means may be provided to prevent the alarm train main wheel 22 from being driven by the main spring except at such times as the clock has been set to sound the alarm.

A member 46 is coiled around the hub 20 between the alarm train main wheel 22 and the flange 24. This member 46 is a resilient member which has a tendency to wrap itself tightly around the hub, and said member 46 is provided with a projection 48 for a purpose to be presently described.

Mounted on the frame plate I 2 is a stop 50 which is adapted to be engaged by the projection 48 of member 46. When the winding arbor I4 is rotated in a clockwise direction to wind the clock, the projection 48 of member 46 will come into engagement with one side of the stop 50 and thereby cause the member 46 to tend to uncoil so that the arbor l4 and the hub 20 may continue to be rotated for the necessary number of turns, usually about nine or ten revolutions, to completely wind the main spring of the clock. When the time-indicating mechanism of the clock has reached the time for which the alarm indicator has been set, the mechanism which normally prevents the alarm from operating is caused to move to such a position that the alarm train main wheel 22 may be driven by the inner end of the main spring 38. The wheel 22 will then be driven by the spring 38 in a counterclockwise direction until the projection 43 comes into engagement with the other side of the stop 58 at which time the member 46 Will coil tightly around the hub 20 to prevent the hub, and the wheel 22 with which the hub is connected, from being further rotated.

It will readily be seen that two stops may be provided on diametrically opposite sides of the hub 20, in Which case the wheel 22 can be driven by the main spring 38 through only one half of a revolution. It is also obvious that the second stop 50 may be provided in any point about the periphery of the hub 28 so that the spring 38 may drive the alarm wheel 22 through any part of a revolution which is found to be desirable. In the preferred embodiment, however, but one stop 5!! is provided. Thus, in said preferred embodiment, alarm wheel 22 will be driven by the spring 38 through substantially one complete revolution which will cause the alarm to be sounded for a sufiicient length of time and yet will not unnecessarily rob the time train of its portion of the power of the main spring.

The member 45 is shown in cross section in Fig. 5 where it will be seen that the member lfi is square. The reason for making this member 46 square is so that its inner surface will engage the hub over alarge area even though only a few convolutions of the member 48 are provided. If the member 46 were round, it will be seen that it would engage the hub only in a line contact so that a large number of convolutions would be necessary in order to provide a substantial frictional contact area with the hub. It is desirable to provide as few convolutions of the member 46 as possible in order that its over-all width will be small. In this manner, the frame plates will not have to be spaced apart by an undue amount.

.As shown in Fig. 5 at 46a, 48b, and 480, it is not necessary that the member 46 be square in cross section so long as it is of such shapethat e its inner surface will contact the hub 20 over a width substantially equal to the total width of the member. To insure maximum efficiency in engagement between the inner surface of member 46 and the juxtaposed surface of hub 20, the

inner surface of member 46 may be finished by a reaming operation.

While the invention has been illustrated and described in its preferred embodiment and has .included certain details, it should be understood that the invention is not to be limited to the precise details herein illustrated and described since the same may be carried out in other ways, falling within the scope of the invention as claimed.

What I claim is:

1. In a timepiece having a time train and an alarm train supported by a frame and a single spring for driving both trains; a winding arbor, an alarm train main wheel mounted upon said arbor, a hub extending in opposite directions from the center of said wheel and rotatable therewith, one end of said hub being constructed and arranged to be engaged by the inner end of said spring, a member extending around the other end of the hub for at least the major portion of the circumference of said hub, said member having a projection extending outwardly from the hub, and a stop mounted in a position to be engaged by the projection.

2. In a timepiece having a time train and an alarm train supported by a frame and a single sprin for driving both trains; a windin arbor, an alarm train main wheel mounted upon said arbor, a hub extending in opposite directions from the center of said wheel and rotatable therewith, one end of said hub being constructed and arranged to be enegaged by the inner end of said spring, a member extending around the other end of the hub for at least the major portion of the circumference of said hub, the surface of said member juxtaposed to said hub being so shaped as to afford appreciable area to frictionally engage said hub, said member having a projection extending outwardly from the hub, and a stop mounted in a position to be engaged by the projection.

3. In a timepiece having a time train and an alarm train mounted between a pair of frame plates and a single spring for driving both trains; a winding arbor, an alarm train main wheel mounted upon said arbor, a hub extending in opposite directions from the center of said wheel and rotatable therewith, one end of said hub being constructed and arranged to be engaged by the inner end of said spring, a member extending around the other end of the hub for at least the major portion of the circumference of said hub, said member having an interior surface substantially parallel with the peripheral surface of said other end of the hub whereby a small number of convolutions of the member will present a large contact area to the hub, said member having a projection extending outwardly from the hub, and a stop mounted in a position to be engaged by the projection.

4. In a timepiece having a time train and an alarm train mounted between a pair of frame plates and a single spring for driving both trains; a winding arbor, an alarm train main wheel mounted upon said arbor, a hub extending in opposite directions from the center of said wheel and rotatable therewith, one end of said hub being constructed and arranged to be en gaged by the inner end of said spring, a member substantially square in cross section coiled around the other end of the hub, said member having a projection extending outwardly from the hub, and a stop mounted in a position to be engaged by the projection.

G. S. ANDREWS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 188,865 Davies Mar. 27, 1877 1,090,648 Pratt Mar. 17, 1914 1,916,033 Baltsois June 27, 1933 FOREIGN PATENTS Number Country Date 310,987 Great Britain May 6, 1929 

